Lhasa is about 3600m above sea level and the air is certainly rare. We took the train from Chengdu to Lhasa which traveled up to over 5000m at the highest point. The train had oxygen you can put directly into your nose. We didn't do it and regretted it. Altitude sickness takes many forms. 1. Worst hangover you've ever had. Headaches. Shortness of breathe. Lethargy. In general, you feel miserable. It took a few days for us to get a little acclimatised to it. There is medicine you can take but I don't know how effective it is. Your best course would be to Google it and make an educated guess as to what you want to do to minimise the effects. If you can, take a week getting there, acclimatise along the way. Lhasa is a magical place on earth and I'll certainly be going back there. over 6 years ago
Most of the people can naturally acclimatize to Lhasa altitude, but some have symptoms of altitude sickness. It is impossible to predict how you will react unless you already traveled in high altitude areas. The good news is that for most, all symptoms will disappear in a couple of days.
It is important to get plenty of rest and sleep, not to exert yourself, drink plenty of water and take it slowly. Here are more tips on how to naturally acclimatize to the altitude in Tibet: https://wondersoftibet.com/7-tips-for-altitude-sickness-prevention/ 10 months ago